Light signal



E. W. MOORE LIGHT SIGNAL July 18; 1933.

Filed Nov. 5, 1927 lNV NTOR WZZ ;ATTORNEY Patented July 18, 1933 UNITEDSTATES PATENT OFFICE EDNIUND W. MOORE, OF ROCHESTER, NEW YORK, ASSIGNORT0 GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK LIGHT SIGNALApplication filed November 5, 1927.. Serial No. 231,292.

This invention relate'sin general to light signals, and has moreparticular reference to such signals which continue to give distinctiveindications upon failures which would normally result in darkindications.

In light signals, such as is particularly used in railway signalling, itis very important, in avoiding danger, to prevent failures of suchsignals since, when such failures result in dark signals, conditionsare'not so completely safeguarded as when the light signal is arrangedto nevertheless continue its active indication.

With the above and other objects in view it is proposed, in accordancewith this invention, to provide a light signal which includes, incombination witha doublet lens combination of lenses, a singleincandescent bulb containing a main filament and a reserve filament,whereby both filaments can be readily positioned close to the inner lensof the doublet combination as is necessary, in such lens-systems, forbeing on focus. The single bulb is carried in a socket mounted on anadjustable bracket andprovided with sighting means for determining whenthe laiilf is properly positioned. i

i ea11s,',controlled in accordance with traffic conditions, is arrangedtomomentarily energlze both of the filaments, together with means forimmediately or shortly thereafter tie-energizingthe reserve filamentwhile continuing the energization of-thenmainfilament, and to operate,upon breakage or burning out of the main filament, to cut the reservefilament into energization. The main filament is placed on focus,whereas the reserve filament is positioned ofi focus and above thereof,whereby to give a somewhat diminished, and also slightly depressed,

beam suflicient for being picked up and recognized by the engineman asthe distinctive signal'indication, but of such a character as to advisehim, and place him on hlS notice, that the signal requires attention.

Further objects, purposes and characteristic features of the presentinvention will appear as the description progresses, reference being hadto the accompanying drawing showing, solely by wayof illustration,

two filaments 10 and 11, which are respechaving a removable rear door 2,and a large opening 3 in the front of the casing within which 1spositioned a doublet lens combination comprising lenses 4 and 5, therebeing a sunshade or visor 6 fastened to the casing.

Carried by a retainin ring 7 for the inner lens 5, is'an adjustingiracket B carrying a lamp base receiving socket 8, in which is receivedan incandescent lamp W The bracket Bgcan be adjusted-to'move the" socket8 in threeplanes substantially at right angles to each other, whereby toposition the lamp 9 'at'the" desiredipoint in the casing relativeoto thedoublet lens, and for a detailed description of this" adjusting.

bracket referencesho'uld be had to co-pend-" ing application SJ N.f131,466 filed August2 5, 1926, now Patent No. 1,822,105.' '1

Also carried by the retaining ring 7 isa sighting device S, fordetermining when the lamp is properly adjusted, and for a detaileddescription of the construction and operation of this device S,reference shouldbe had to co-pending application S. N..131,467, filedAugust 25', 1926, now Patent No. 1,794,586.

Positioned within the bulb of lamp are tive'ly main and reservefilaments, the lament 10 when properly positioned being on focus, whilethe filament 11 is ofl of focus and above thereof.

As shown in Fig. 2, the light signal is controlled in accordance withtraflic conditions,- as for example, by means of a track relay TR,connected across track rails 30, toin turn control a line relay L whichin turn controls the energization of the lamp filaments.

For automatically maintaining the reserve filament 11 de-energized,while the main filament is energized when conditions correspond toenergization of the signal exist, is a light-out relay OR. The energyfor energizing the light signal is derived fromthe secondary of atransformer T, the primary of which is fed from any suitable desiredsource of electrical energy.

As shown in Fig. 2, traffic conditions correspond to the energization ofthe light signal. With relay TR energized, its finger 31 is attracted,to thereby energize relay L, through a circuit obvious from the drawing.

With relay L energized, and its contact finger 12 in attracted position,energy from the secondary of transformer T momentarily energizes both ofthe filaments 10 and 11 through circuits including; secondary oftransformer 'T, contact finger 12 and front point of relay L, wire 13,and then, in multiple; first through filament 10, wire 14, and

relay CR to the common'point 15, and, sec- 0nd, through reserve filament11, wire 16, re-

actance 17 (which is chosen to equal the reactance of relay CR), wire18, and contact finger and back point 19 of relay CR to the common point15; and thence, by wire 20, back to the secondary of transformer TLight-out relay GR is arranged to pick up on energization to thus breakthe above traced energizing circuit for reserve filament 11 at itscontact finger 19, without affecting the energization of main filament10.

Let us now assume that the main filament 10 burns out, is broken, or dueto any other cause breaks the circuits passing through relay CR. Onde-energization of relay CR, its contact finger 1 9 assumes retractedpositlon, to energize reserve filament 11 through its energizing circuitas described just above with regard to the momentary energization ofreserve filament 11 on initial energization of the light signal.

This reserve filament, as shown, and as explained above, is oilfocus,-and above focus, whereby to give a weaker beam. than that of thema n filament, and to direct this weaker beam slightly downwardly fromthe direction of the beam from the main filament. In certain conditionsit has been found desirable to arrange the reserve filament to give abeam of per cent of the intensity of that of the main filament, and toposition it so that its beam will be projected in a direction depressedfrom the main beam from 2 to 3. In all events, the reserve filament 11is so 0- sitioned that its projected beam, while being weaker than themain beam, and depressed downwardly therefrom, will still be sufiicientfor the engineman to readily pick up the light signal indication, whileat the same time being advised by the different characteristics of thisindication from the usual indication, that something is wrong with thelight signal, and that inspection and repair be .ment lamp and given torectify conditions.

It should be borne in mind, that in order to readily, or in fact,possibly, place the two filaments, main and reserve, in the desiredrelative position one to the other, they should both be placed in asingle incandescent bulb rather than in two separate lamp bulbs.

Furthermore, it is most important,in order to utilize a large solidangle of the total light flux emitted 'that a doublet lens combinationbe used. It is well known by those skilled in this art that the focalpoint of a doublet lens combination lies nearer to the inner surface ofthe inner lens of the combination, than does the focal point of eitherof the two component lenses making up the combination, whereby a largersolid angle of light fluX can be availed of, than without such a doubletcombination. With such a combination, however, of lenses, it would bedifficult, or perhaps impossible, to place the two filaments in questionclose enough to the inner surface of the inner lens if the filamentswere placed in separate lamp bulbs. It therefore appears quite obviousthat the characteristics of the doublet lens combination used, and ofthe two filaments in a single lamp bulb, mutually cooperate with eachother to permit their needful combinative combination.

It is, of course, wholly within the purview of this invention, to employthe double filaits automatic control means, in light signals other thanthat shown and described above. For example, it can be advantageouslyused in a light signal of the type which employs a single light sourceand a movable spectacle carrying several different color glasses, allwith a single casing, whereby'a single light unit displays severalsignal indications.

In concluslon, 1n accordance with this invention, when traflicconditions are such as to cause energization of track relay TR, the twofilaments 10 and '11 are momentarily. energized, after which, thelight-out relay CR will operate to de-energize the reserve, filament,providin the main filament is intact, until such time as the mainfilament fails, whereupon relay GR is de-energized and cuts in thereserve filament 11 to give the desired reserve indication, which issuflicient for the engineman to pickup the indication, and at the sametime to advise him, due to the somewhat diminished and depressed beam,that inspection and repair of the light signal is necessary. p

The above rather specific description of the invention is given solelyby way of illustration, and is not intended in any manner whatsoever, ina limiting sense. Obviously, the invention can assume various differentphysical forms and is susceptible of numerous modifications, and allsuch forms and modifications, are intended to be covered by thisapplication, as come within the appended claims.

Having described my invention, I now" 1. In a light signal for railwaysignal sys* tems, a casing, a doublet lens system. in the front of thecasing, a lamp bulb within the casing and projecting into the cupportion of the inner lens, a main filament and a reserve filament in thebulb, and means for automatically causing energization of the reservefilament upon failure of said main filament, the main filament beingadjusted on the focus of said lens system, and the reserve filamentpositioned off, and above, such focus whereby to indicate failure of themain filament by the lessened intensity and the position of the beamproduced by the reserve filament.

2. Ina light signal, a casing, a doublet lens combination in thefront ofthe casing, a single incandescent bulb positioned at the focus of saidlens combination, a main filament in the bulb and on focus, a reservefilament in the bulb and'ofi focus, and means for automatically cuttingthe reserve filament out of an energizing circuit when the main filamentis intact and is in an energizing circuit, and for energizing thereserve filament upon failure of the main filament during itsenergization whereby to indicate failure of the main filament by thelessened intensity and the position of the beam produced by the reservefilament.

EDMUND W. MOORE.

